Existing “gesture + gaze” multimodal interfaces for Computer-aided design (CAD) still suffer from fixed mapping relationships between interactive operations and CAD commands. In this paper, we proposed a multimodal interface CGGI-CM: Combining Gesture and Gaze Interface for CAD Modeling Based on Context Model. By introducing a context model that can describe human-computer interaction scenarios in CAD modeling, a flexible one-to-multi mapping of interactive operations to CAD commands was achieved and the number of CAD commands mapped by gesture increased by 100%. To verify the performance of CGGI-CM, a user experiment was conducted and the results were compared with those of a conventional “mouse + keyboard” interface (MKI). The experiment results showed that CGGI-CM posted superior performance in task completion time compared with MKI. For task operation accuracy, there is little difference between CGGI-CM and MKI. Moreover, users found that CGGI-CM is more intuitive and natural than MKI in CAD modeling.

Currently, tacit knowledge has attracted increasing research attention. However, the theoretical foundation of tacit knowledge is still not well formulated, because the researches are very disperse. This work provides a review of the current researches. First, the definition of tacit knowledge is discussed by answering several questions. Next, tacit knowledge sharing, tacit knowledge quantization are identified as two research topics in the current research community. Following that, the technical progress of each topic is summarized and analyzed. Finally, we provide a thumbnail of the researches and identify three research consensuses to answer where we are. While, seven research directions are identified to answer where we shall go.